Add config file env arg to server start command

README.md

@@ -67,7 +67,7 @@ This app was built from the [react-slingshot](https://github.com/coryhouse/react
 
 6. **Run the example app**
 
-   `npm start -s`
+   `CONFIGFILE=config/config_[workflow].yaml npm start -s`
 
    This will run the automated build process, start up a webserver, and open the application in your default browser. When doing development with this kit, this command will continue watching all your files. Every time you hit save the code is rebuilt, linting runs, and tests run automatically. Note: The -s flag is optional. It enables silent mode which suppresses unnecessary messages during the build.